Novo
by IndigoStarling
Summary: Four year old Jessamine and her older sister Cassa's home is invaded by a demon. But Cassa knows nothing of demons and the Shadowhunter world...what happens when her Shadowhunter-hating parents decide to tell her the truth? Will she embrace the life she never knew she could have? Mutantur omnia nos et mutamur in illis. One-shot. T for violence. Please r&r!


**Hello! Celeste here.**

**So basically this is a one-shot about Jessamine's sister- an OC of mine. The theory is that we never knew she existed.**

**The words in italics at the very end are words Cassa is writing when she is older- almost a narrative.**

**This is my very first Infernal Devices story, so PLEASE tell me if you like it!**

The crashes and bangs from downstairs were deafening, shaking the grand old house and punctuating the air with screams and battle cries. The girl, crouched underneath a table in a room that was clearly her bedroom, squeezed her eyes shut and tried as hard as she could to shut out the noises.

The girl was about ten years old. She had curling dark red hair, a slim figure and looked very dainty in her cream nightgown. She was in a ball shape, too terrified to move.

She could hear a man's voice- her father, yelling her name. "Cassa! Cassa, hide for me! Hide for daddy!" His voice was scratchy and desperate. The girl removed her hands from her ears to hear this, but when she heard the scream of her mother she clapped them on her ears again.

"So, there is a girl upstairs, then, is there?" sneered a horrible voice. It wasn't male or female, it was very strange and creepy. Of course, that scared Cassa more than anything, more than even the fact that it was coming to get her.

She felt it in the floor, every time the talking creature thumped on the stairs. Cassa swallowed, petrified, and began to tremble.

But the creature went the other way, down the left corridor. And Cassie suddenly heard a dull bang and the creature roared- someone hit him.

_Oh no,_ thought Cassa numbly. _Jessamine._

"Take THAT! You, you monster!" A tiny voice yelled out from the room the creature was in. _No, _thought Cassie. _Jessie is only five. He'll _kill_ her._

Suddenly Cassa saw red. She filled with rage from top to toe and crawled out from under the table. By now she could hear little Jessie's screams of pain and terror.

Cassa yanked open her clothes drawer and from underneath the layers of dressed found a short, silver dagger. Her father always told her to say a certain word when holding this dagger and it could kill monsters. He'd hidden it there for safekeeping- it was supposed to kill her imaginary monsters under the bed.

Now she spoke the word, and for the first time the blade she held in her small hand was about to be used against a _real _monster.

"_Virtus."_

The blade lit up with a beautiful strong, blinding light. Cassa ran as fast as she could, against her better judgement, to the room where her little sister was screaming and entered it.

Cassa stood stock still.

It looked like a skeleton of a large saber-toothed tiger, with red flaps of skin peeling off and hanging in a revolting manner. It had rot growing on the pieces of skin, and Cassa retched. It smelt like…death.

Jessamine was lying on her back with the creature stroking her face sadistically with a claw, and a long red line of blood was appearing in the claw's wake. _It must be incredibly sharp_, though Cassa, who despite of the horror was using her intellect to her best advantage.

Cassa noticed that it only had one organ, a dripping green heart, attached to the skeletal ribcage by a pulsing strip of pink skin. It looked like a spider's web, in which the heart was incased. Cassa knew she had to stab the heart.

"Over here!" she shouted. The creature whipped its head around to face her, and with a swoop in her stomach Cassa realised it had eyes dangling by its nose by threads. It smiled.

Quickly, she launched forward and sliced with the dagger. One of its eyes came clean off, but it didn't seem to use them anyway. She blew the hair out of her eyes and pushed Jessamine behind her.

The creature growled while smiling, as if it were all a game. He tilted his head to the side and Cassa heard a horrible crack.

Her first priority was to get her little sister out of there.

Cassa ran forward again and whirled the blade across her body to hit the creature in the leg. The blade slowly sunk into bone, and Cassa couldn't let go and the creature knew it. So it stuck a fang into her arm.

Cassa screamed and pulled the blade back. There was a smell of burning, and the creature realised its leg was being burned right off. It roared ferociously, and Cassa turned around to see where Jessamine was. She had toddled out of the door- and Cassa sighed with relief.

But her arm. It stung like nothing Cassa had ever felt before. It was so painful; like fire tearing its way into her body. But she couldn't stop.

Cassa shifted her weight to her left foot and her blade to her uninjured right arm. The creature reared up onto its hind legs, and Cassa took the opportunity to slide forwards underneath the creature and through its back legs, stabbing as hard as she could upwards when she was below the pulsing web and heart.

She felt burning slime coat her hands, and she let go of the dagger. It was like acid. She slid the whole way through the creature's legs and sat up, turning around to see the creature melt into a stomach-retching heap of ashes and burned flesh. Cassa threw up then and there, and blacked out.

Her dreams were full of the creature, sinking its fang into her arm, cutting Jessie, thumping up the steps. She relived it all, except this time there was a voice.

"YOU ARE A PAWN."

That was all the voice said, over and over until her mind was ringing. She didn't even know what it meant, but it resounded in her head until she snapped awake, clutching her hands to her forehead.

Throughout the next day, Cassa drifted in and out of consciousness. She saw her father, her mother, even once little Jessamine, all talking to her in soothing tones. She also saw a strange swirling black mark on her left arm and right hand- it was beautiful.

Cassa woke up properly a week after the monster had invaded her home. She sat up in the bed in her bedroom, and found her mother sitting at her bedside. Her mother looked weary and sad, but had a smile on her face that didn't quite reach her eyes. Cassa noticed there was a swirly black mark on her mother's collarbone as well- but her mother pulled her dress collar up to hide it.

"Good morning, darling," said Cassa's mother. Cassa smiled and felt more awake than ever.

But she couldn't keep that disgusting creature from entering her mind once again. "What was that thing, mother?" Cassa asked, with a persuasive tone. To her surprise her mother put her head in her hands.

"We said…we said this wouldn't happen any more…" she whispered.

"What are you talking about?" asked Cassa, anxiety building.

Her mother looked up, the lines of age very visible on her face although she wasn't more than 40. "Your father and I. We promised… I think I'd better tell you from the start."

Cassa nodded and leaned forward. She wasn't going to let her mother away without answers; she needed to know.

"Your father and I, and Jessamine and yourself, are all a…special…race of humans called _Shadowhunters_," said her mother. At the word 'Shadowhunters' her lips curled into an expression of distaste. "Shadowhunters are supposed to hunt demons. That was what you fought."

"Why have you not told me before?" said Cassa curiously. She wasn't surprised- after all, what was there left to be surprised about?  
"We have not told you or your sister because when you were born your father and I swore to keep you both safe. We left the Clave; we decided never to be Shadowhunters again. We thought it would work.

"But now I see that we could never have quelled you being a Shadowhunter. You have those fighting instincts…but there is still time to protect Jessamine."

"What do you mean? I don't understand…" said Cassa, frowning.

"We placed Marks on you to heal you, special Shadowhunter marks. Your Shadowhunter instincts will be stronger than ever, but Jessamine has no idea of any of this. We need to keep her protected."

"Are you…are you saying I have to leave?" Cassa was shocked.

"You might. Being a Shadowhunter is…repellant to your father and I, so we need you to make a choice. This is very hard for me."

"But…but I am your daughter! This is not fair! It was not my fault that I had to fight that…demon to protect you all! I have done more than anyone!" Cassa had raised her voice.

"Cassa, dear, do not fret. Please be calm. I am simply suggesting that you read this book and make your decision about whether you want to be a Shadowhunter or not." Her mother handed her a large black volume with gold lettering, called "_The Shadowhunter Codex_".

"But you do not want me here, do you?" said Cassa. "I can tell you think Shadowhunters are filth."

"My little Cassa, I am doing what is best for the family," her mother looked drawn and guarded. "If you do decide to go, we will send you to the Shadowhunter country, Idris. It is very beautiful, I am sure you would love it…"

Cassa grabbed the book and got out of bed, feeling perfectly fine except for a growing feeling of distrust. She was only ten- children grow up feeling reliant of their parents, and yet now Cassa felt herself drifting away.

She ran out of her bedroom and down the stairs before hiding herself in a secret place in the garden that she had never shared with anyone but Jessamine.

Jessamine.

Cassa knew that if she left she would be leaving behind the person she cared most about in the world, her beautiful little sister. She remembered holding Jessie as a baby, playing with her, never fighting. They had a perfect relationship. But perfect things never last, like autumn or china teacups.

Cassa sat down on the grass and began to read. She looked a picture, in her pretty green dress with her long red hair floating in the wind. Even the growing expression of wonder on her face as she slowly read the pages in her lap.

Werewolves, vampires, faeries, and warlocks…the names were beautiful and wild. Unlike many other children Cassa had not grown up with fairy tales like these, as her parents wanted to keep her separate from this world. So they were all like wondrous dreams.

And Shadowhunters, the best of all. Offspring of angels. Cassa could not understand her parents' decision to leave.

That day, Cassie made her decision.

She would no longer be Cassa Lovelace of London. She would be known by her full name. She would be Cassalia Lovelace of Idris.

_Sometimes the hardest choices are the ones we know are best for us, but we will be leaving behind the ones we love most. But it must be done, and we must move on…_

_That day was the day I made the decision to restart my life, to be reborn and changed for the better._

_But I think I left a little piece of myself behind, in the tiny hand of the little girl who made my life whole, yet now has broken me. I would heal, of course, like all the battle wounds I was yet to gain._

_When I was to return, my sister would be gone._

**Well? Did I do okay?  
PLEASE TELL ME if you want me to make it longer! I'd love to, I'm just not sure if I'm doing Infernal Devices justice. LET ME KNOW!**

**Love you all,**

**Celeste xx**


End file.
